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研究了以微波雷达作为相对测量设备的追踪星与近圆轨道上运行的目标星之间的自主相对导航问题。通过对卫星相对运动方程简化得到了线性的卫星相对运动方程。采用以雷达输出确定的直角坐标系下的相对位置作为量测,避免了直接使用雷达输出作为量测时量测方程的非线性问题,并给出了间接量测噪声方差矩阵的构造方法。根据线性的相对运动方程和量测方程设计了基于标准卡尔曼滤波器的相对导航算法。根据某微波雷达的性能参数进行的仿真结果表明:该算法与采用雷达的直接输出和EKF的算法导航精度相当,然而该算法避免了求解雅可比矩阵的繁琐过程,使滤波器的设计工作得到简化。
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相对轨道自主确定方法的改进 总被引:4,自引:1,他引:3
编队飞行卫星相对轨道的确定具有重要意义。本文提出一种完全自主的定轨方案,在利用星间测量信息实现编队飞行卫星自主定轨的基础上,引入太阳敏感器测量信息,利用扩展卡尔曼滤波算法提高环绕星相对轨道确定精度。仿真结果验证了这种导航方案和算法的有效性。 相似文献
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基于星间测距增强的卫星编队GPS相对导航研究 总被引:1,自引:0,他引:1
针对单纯差分GPS系统在精度、连续性、实时性方面存在的问题,提出了一种星间测距增强差分GPS的卫星编队组合相对导航方案。该组合相对导航系统由编队卫星中分别安装的GPS接收机、星间RF测量传感器,以及主星中运行的导航处理器组成,其中星间RF测量传感器集成了窄带通信功能,可在进行星间距离测量的同时同步进行GPS数据的互传。采用扩展Kalman滤波算法,结合简化动力学模型和GPS以及RF测量数据实现卫星编队的相对位置与速度的高精度实时递推解算。用模拟器采集数据进行了仿真验证,结果表明:在星间测距数据辅助下,星间基线长度在星间测距工作的30km范围内时,实时相对导航精度优于1mm;系统在GPS信号中断时仍可连续输出满足精度要求的相对位置、速度数据;系统初始化时间由单纯差分GPS相对导航系统的几十个历元降低到单点。 相似文献
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基于三轴磁强计与雷达高度计的融合导航算法 总被引:3,自引:1,他引:3
为了减小近地轨道(小于1000km)地磁导航的估计误差协方差,提高导航的可靠性和准确性,在地磁导航系统中引入雷达高度计作为一个新的测量设备,提出了一种基于三轴磁强计与雷达高度计的融合导航算法。该算法取卫星的位置和速度向量作为状态向量,建立状态方程;取卫星周围的磁场强度和卫星到星下点实际海平面距离求出的地心距,作为观测量建立观测方程;利用扩展卡尔曼滤波构成一种融合导航算法。仿真结果表明,提出的融合导航算法对轨道位置的估计误差小于20米,速度的估计误差小于1米/秒,导航算法的精度和收敛性都优于使用单一地磁导航的系统。 相似文献
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利用雷达高度计及星敏感器的多处理器卫星导航 总被引:1,自引:0,他引:1
鉴于当前单一处理器导航计算机结构给导航算法带来的约束及并行多处理器技术的日益成熟,提议卫星导航采用两个处理器并行的计算机结构,将卫星自主导航工作中轨道状态估计和状态预报分外在不同的处理器上处理。依据这一分工思路,提出近地海洋卫星利用雷达高度计及星敏感器实现自主导航的方法,并给出一个简单的导航模型及导航算法。通过计算机仿真检验了利用雷达高度计及星敏感器为近地海洋卫星提供导航的可行性,也验证了导航结构的适用性。 相似文献
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Wolfgang Keydel 《Acta Astronautica》1984,11(1):3-14
(Possibilities and Limitations of Microwave Systems for Satellite Remote Sensing)—Microwaves are applied in satellite remote sensing in both active, i.e. radar systems and in passive, i.e. microwave radiometer systems. The advantages and disadvantages of active and passive microwave systems in comparison to each other and to optical systems are discussed shortly. It becomes evident that radar has advantages over microwave radiometry due to its ranging and velocity-measurement capability, due to its SAR-capability with its extremely fine resolution and due to the fact that no major theoretical limitations exist for the obtainable measurement accuracy.The most important radar systems for Earth and ocean observations from satellites are altimeter, scatterometer and imaging radars with real or synthetic aperture. The physical and technical basics of these types of radar are presented together with some applications. Examples for remote sensing data and results obtained from different microwave remote sensing systems show the present state of the art and the present possibilities and limitations of microwave systems for satellite remote sensing. 相似文献
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针对时变拓扑卫星集群的相对导航需求,提出了基于图论的时变拓扑分布式一致性无迹卡尔曼滤波算法。首先给出了固定拓扑卫星集群的相对运动方程、测角测距测量模型和无迹卡尔曼滤波算法,然后考虑测角失效时相对导航系统不可观或弱可观的问题,结合矢量环一致性约束,构造了一致性无迹卡尔曼滤波算法,以提高系统的可观度;在此基础上,针对时变拓扑卫星集群,以滤波精度为优化指标,在图论的基础上利用Dijkstra算法对卫星集群的时变拓扑结构进行重构,并将重构后的拓扑结构应用于卫星集群相对导航。仿真结果表明所提算法能有效改善不完备测量带来的模糊轨道问题,并且能够实现实时的拓扑重构,以满足时变拓扑星群的相对导航精度要求。 相似文献
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TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurements) is an innovative formation-flying radar mission that opens a new era in spaceborne radar remote sensing. The primary objective is the acquisition of a global digital elevation model (DEM) with unprecedented accuracy (12 m horizontal resolution and 2 m relative height accuracy). This goal is achieved by extending the TerraSAR-X synthetic aperture radar (SAR) mission by a second, TerraSAR-X like satellite (TDX) flying in close formation with TerraSAR-X (TSX). Both satellites form together a large single-pass SAR interferometer with the opportunity for flexible baseline selection. This enables the acquisition of highly accurate cross-track interferograms without the inherent accuracy limitations imposed by repeat-pass interferometry due to temporal decorrelation and atmospheric disturbances. Besides the primary goal of the mission, several secondary mission objectives based on along-track interferometry as well as new bistatic and multistatic SAR techniques have been defined, representing an important and innovative asset of the TanDEM-X mission. TanDEM-X is implemented in the framework of a public–private partnership between the German Aerospace Center (DLR) and EADS Astrium GmbH. The TanDEM-X satellite was successfully launched in June 2010 and the mission started its operational data acquisition in December 2010. This paper provides an overview of the TanDEM-X mission and summarizes its actual status and performance. Furthermore, results from several scientific radar experiments are presented that show the great potential of future formation-flying interferometric SAR missions to serve novel remote sensing applications. 相似文献
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静止轨道气象卫星观测系统发展设想 总被引:1,自引:1,他引:0
介绍了静止轨道气象卫星发展的现状。对国内外静止气象卫星的平台能力和探测仪器性能进行了对标与分析。根据我国静止气象卫星应用需求,给出了所需的新型遥感仪器的需求。讨论了静止气象卫星的发展趋势。介绍了静止气象卫星采用光学成像星、探测星(光学、微波)、降水测量星组合配置,在同步轨道上同位或异位进行观测的发展设想,以及需配置的先进可见光红外成像仪、闪电成像仪、高光谱垂直探测仪、地球辐射收支仪、太阳X-EUV成像仪、地球静止轨道先进微波探测仪、地球静止轨道降水测量雷达等的主要功能与性能。 相似文献
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This paper analyses the fuel consumption of interferometric radar missions employing small satellite formations like, e.g., Cross-track Pendulum, Cartwheel, CarPe, or Trinodal Pendulum. Individual analytic expressions are provided for each of the following contributions: separation from a simultaneously injected master satellite, formation set-up, orbit maintenance, formation maintenance, and distance maintenance. For this, a general system of equations is derived describing the relative motion of the small satellites in a co-rotating reference frame. The transformation into Keplerian elements is carried out. To evaluate fuel consumption, three master satellites are assumed in different orbital heights, which are typical for Earth observation missions. The size of the exemplarily analysed formations is defined by remote sensing aspects and their respective fuel requirements are estimated. Furthermore, a collision avoidance concept is introduced, which includes a formation separation and formation set-up after a desired time period. 相似文献
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Ken''ichi Okamoto Takeyuki Ojima Shin Yoshikado Harunobu Masuko Hideyuki Inomata Nobuyoshi Fugono Toshiharu Sakai Hiroshi Okamura Masanobu Tsudo 《Acta Astronautica》1982,9(12):713-721
The remote sensing of precipitation, especially rain by the spaceborne weather radar is an important subject which has not been realized. The system design and examination of the spaceborne weather radar which is called as the spaceborne microwave rain-scatterometer are performed by considering user's requirements to observe rain, the restrictions derived from the interface with satellite and the state of the art and the possibility of spaceborne microwave technology. Characteristic parameters for spaceborne microwave rain-scatterometer are determined based on the user's requirements for the system. Functions and performances of each subsystem (antenna, transmitters, receivers and data transmission processor) with the detailed block diagram of the total system of spaceborne microwave rain-scatterometer are shown. All of the critical items of hardware in the development of spaceborne microwave rain-scatterometer are also discussed. 相似文献
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高精度星间微波测距技术 总被引:5,自引:0,他引:5
卫卫跟踪(SST)技术是目前地球重力场测量最有价值和应用前景的方法之一。高精度K波段星间微波测距系统(KBR K Band Ranging System)低低卫卫跟踪(SST-Ⅱ)重力卫星的关键有效载荷,它是一微米量级的测距系统,通过处理高精度的星间距离和距离变化率数据,可以恢复出地球重力场。在研究星间双路微波测距原理的基础上,提出了一种KBR系统的基本结构,详细描述了数据处理过程和KBR系统研究需要突破的关键技术,分析了国内目前的研究水平,给出了我国未来开展KBR系统研究的一些建议。 相似文献